/*
 * gybon - Core modules for Google Yahoo Rich Application Framework
 *
 * Copyright (c) 2009, Yves Cuillerdier
 * All rights reserved.
 * 
 * This software is licensed under the new BSD License:
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, 
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the documentation 
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the author nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * @version 0.1.0
 */
package gyraf.wrapper.client.event;

import yocef.client.EventBind;
import yocef.client.EventGlue;

import com.google.gwt.core.client.JavaScriptObject;

/**
 * Utility class to build event handlers.
 */
public class EventHandlerUtil {

	/** Static utility class */
	private EventHandlerUtil() {
		// cannot be instantiated
	}

	/**
	 * Javascript handler for an event without parameters.
	 * <p>
	 * This handler is typically used in the {@link EventGlue#accept(EventBind)}
	 * method to provide an handler to javascript event listener.
	 * <p>
	 * Example: Binding the "onStart" event of a YUI Anim object
	 * 
	 * <pre>
	 * &#064;Override
	 * public boolean accept(final EventBind binding) {
	 * 	final Object element = binding.getSource();
	 * 	if (!(element instanceof Animation)) {
	 * 		return false;
	 * 	}
	 * 	final Animation anim = (Animation) element;
	 * 	JavaScriptObject handler;
	 * 	final Event event = binding.getEvent();
	 * 	if (event == AnimEvent.ElementAnimationStart.event()) {
	 * 		handler = Handler.getNoParamHandler(binding);
	 * 		registerOnStart(anim.getJsElement(), handler);
	 * 	} else if (event == AnimEvent.DuringElementAnimation.event()) {
	 * 		...
	 * 	} else {
	 * 		return false;
	 * 	}
	 * 	...
	 * 	return true;
	 * }
	 * </pre>
	 */
	public static native JavaScriptObject getJsNoParamHandler(
			final EventBind binding) /*-{
		var handler = function() {
			// The event from the binding
			var event = binding.@yocef.client.EventBind::getEvent()(); // un Lyocef/client/Event;
			// The element from the binding
			var element = binding.@yocef.client.EventBind::getSource()(); // un Ljava/lang/Object;
			// The context from the binding
			var context = binding.@yocef.client.EventBind::getContext()(); // un Lyocef/client/EventContext;
			// The action from the binding
			var action = binding.@yocef.client.EventBind::getAction()(); 
			// Call action
	        return action.@yocef.client.EventAction::handle(Lyocef/client/Event;Ljava/lang/Object;Lyocef/client/EventContext;Lyocef/client/EventParams;)(event, element, context, null);
		};
		return handler;		
	}-*/;
}
